This is just part 1 of our review of the WWII POW site. We visited without an appointment, but plan to return when we can actually see the inside of the museum
Although Google shows the site as open 24 hours, all you can see without an appointment is the guardhouse and a few old foundations down the road by the museum.
We have shared a photo from the door of the museum showing the phone number to call to schedule a tour. We will update our review after we can come back and have the tour. We highly recommend getting to see the inside of the museum, so definitely call ahead for an appointment.
One good thing was that the guard house has a guest book and some flyers available that explain a lot of information about the camp. The POW brochure is very informative, and they also had a brochure of other Concordia places of interest.